Golf ball parting line configuration and mold

ABSTRACT

A golf ball comprises two generally hemispherical portions joined together at a parting line and comprising dimples on respective outer surfaces thereof. The parting line comprises a repeating pattern of curved segments alternating with straight segments. The parting line crosses a geometric equator of the golf ball, and wherein the parting line intersects at least one dimple bordering the equator. A mold for producing a golf ball is also described.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.12/969,452, filed Dec. 15, 2010, which is incorporated herein byreference.

FIELD

The present application relates to golf, and in particular to a golfball having a new parting line configuration and a mold for producingthe new configuration.

DESCRIPTION OF RELATED ART

Golf balls are typically provided with dimpled surfaces because the“dimple effect” results in the desired turbulent flow separation earlierin ball flight, which produces less drag and yields longer distanceshots.

Golf balls are typically produced by pressing together two hemisphericalmold halves that form a dimple pattern in a suitable material, such as asynthetic resin or other material, contained in the mold. Inconventional approaches, the resulting golf ball may have a noticeablebreak in the dimple pattern in the area of the parting line. In thiscase, the dimples are separated slightly to make room for the partingline, which results in a perceptible parting line between the halves ofthe ball. Efforts have been made to configure the parting line tominimize its effect on the dimple pattern.

There is still a need, however, to provide a high performance golf ballhaving a highly regular dimple pattern that provides consistent flightindependent of the point on the ball at which it is struck.

SUMMARY

Described below are implementations of a golf ball having a new partingline configuration that addresses some of the problems associated withconventional golf balls, as well as suitable molds for producing the newgolf ball.

According to a first implementation, a golf ball comprises two generallyhemispherical portions joined together at a parting line and comprisingdimples on respective outer surfaces thereof. The parting line comprisesa repeating pattern of curved segments alternating with straightsegments, wherein the parting line crosses the geometric equator of thegolf ball, and the parting line intersects at least one dimple borderingthe equator.

In some implementations, the parting line intersects exactly one dimple.

In some implementations, the straight segments of the parting line arespaced apart from the equator. The curved segments of the parting linemay have their respective inflection points on a first side of theequator and the straight segments of the parting line may be on a secondside of the equator opposite the first side. The repeating pattern maybe repeated approximately every 72 degrees about each hemisphericalportion.

The curved segments and the straight segments may be joined together atjunctions each having a fillet radius. The dimples may have asubstantially uniform diameter. The dimples may have a substantiallyuniform depth. The parting line may be bordered by about 30 dimples oneach side.

The parting line may extend between dimples except at the point wherethe parting line intersects the at least one dimple. Each of the curvedsegments may cross the geometric equator of the golf ball. In someembodiments, none of the straight segments crosses the geometric equatorof the golf ball.

According to another implementation, a golf ball comprises two generallyhemispherical portions joined together at a parting line and comprisingdimples on respective outer surfaces thereof, wherein the parting lineis defined by a first function comprising a sine-like wave superposedwith a second function to yield a repeating pattern of curved segmentsalternating with straight segments. The parting line may extend aboutthe golf ball, intersecting a bordering dimple and remaining spacedapart from other bordering dimples.

The two generally hemispherical portions may be slightly asymmetricalrelative to each other.

In some implementations, the parting line has a maximum peak-to-peakamplitude of 3°. In some implementations, the parting line has a maximumpeak-to-peak amplitude of 1.5°.

In some implementations, the golf ball has a geometric equator, thegeometric equator extends around the golf ball and the parting lineoscillates about the equator as it extends around the golf ball.

According to one implementation, a golf ball mold comprises upper andlower sections each having projections for forming dimples in an outersurface of a golf ball, and mating surfaces on the upper and lowersections comprising curved segment forming surfaces alternating withstraight segment forming surfaces. One of the mating surfaces canintersects with one of the projections so that a resulting segment ofthe parting line on the golf ball will intersect a dimple on the golfball. All other mating surfaces can be spaced from the projections suchthat the remaining curved segments and remaining straight segments ofthe parting line to be formed on the golf ball do not intersect any ofthe dimples.

In some embodiments, the one of the mating surfaces that intersects withone of the projections corresponds to a straight segment formingsurface.

These and other embodiments are described more fully below, withreference to the following drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a golf ball having the new parting line.

FIG. 2A is a magnified view of a section of the golf ball of FIG. 1showing the parting line in greater detail.

FIG. 2B is another magnified view of a section of the golf ball of FIG.1 showing the parting line.

FIG. 3 is a sectional view in elevation of an exemplary mold apparatusfor making the golf ball of FIG. 1.

FIG. 4 is a perspective view of a lower portion of the mold apparatus ofFIG. 4.

DETAILED DESCRIPTION

FIG. 1 is a perspective view of a new golf ball 10 formed from a firstportion 12 and a second portion 14 that are joined together at a moldparting line 16. As shown in FIGS. 2A and 2B, the parting line 16straddles the ball's equator E as it circumscribes the ball, with curvedsegments 20 alternating with straight segments 22. In general, theparting line 16 “interdigitates” or weaves between the twocircumferential rows of dimples 18 that border or intersect the equatorE. There are about 28-30 bordering dimples in each row that borders theequator E. In the implementation of FIG. 1, the equator is bordered by60 dimples, i.e., 30 dimples on the “north” side of the equator and 30dimples on the “south” side of the equator.

FIG. 2A shows an enlarged section of the golf ball 10 in the area of theparting line 16, illustrating that the straight segments 22 are entirelyon one side of the equator E, and the curved segments 20 cross theequator E, but have their maxima/minima 24 on the side of the equatoropposite the straight segments 22.

FIG. 2B is another enlarged section of the golf ball 10, whichillustrates that the parting line 16 follows a repeating pattern thatgenerally repeats n times about the circumference of the ball. In theillustrated implementation as shown in FIG. 2, the repeating patternrepeats five times about the circumference of the ball. Stateddifferently, the pattern is repeated every 72 degrees about the 360degree circumference of the ball, or is said to have a period of 72degrees. It should be noted that although the pattern is repeated asdescribed, in preferred implementations there is only one point 26 onthe parting line 16 that contacts one of the dimples 18, as describedbelow in greater detail.

A representative instance of the repeating pattern is illustrated inFIG. 2B beginning at the point labeled 0° and extending to the pointlabeled 72°. As can be seen at the 0° point, the pattern starts at ajunction between the end of a straight segment 22 a and the beginning ofa curved segment 20 a, where the intersection is the closest point tothe equator E on any of the straight segments 22. In the same way, themaxima/minima 24 a of the curved segment 20 a is spaced away from theequator E by a maximum amount. From 0° to 72°, the straight segments areprogressively positioned farther from the equator E, and the curvedsegments have their maxima/minima positioned closer to the equator E. Anidentical instance of the pattern is shown between 288° (i.e., −72°) and0°.

In the illustrated implementations, the curved segments 20 have acurvature that very closely matches the radius of the dimples. Forexample, for a dimple having a radius of about 2.1 mm, the radius ofcurvature of the curved segments 20 is about 2.2 mm. In the sameexample, the length of the straight segments 22 is about 1.06 mm. In theillustrated implementations, the parting line 16 “touches” or iscoincident with one dimple at one point along its edge. In theillustrated implementation, the point 26 at which the parting line 16 iscoincident with a dimple can be located about midway along one of thestraight segments.

Thus, there is a slight departure in the repeating pattern, and in oneinstance, rather than approaching an adjacent one of the dimples 18, oneof the straight segments 22 intersects the adjacent dimple at the point26. In the illustrated implementation, the parting line 16 is moved tolocate the point 26 correctly. In other embodiments, it would bepossible to change the shape and/or size of one of the dimples to locatethe point 26 correctly.

The point 26 can be a point of tangency between the curved periphery ofthe dimple and the intersecting straight section. In otherimplementations, the point 26 may be on a curved segment or at a filletor other junction between a straight section and a curved section. Inother implementations, the parting line 16 may be configured to touchmore than one dimple, and preferably, about five dimples or fewer.

In some implementations, the repeating pattern of the parting line 16can be defined as a superposition of two wave forms. The first wave formcan have a relatively long wavelength, and the second wave form can havea relatively short wavelength. For example, the parting lineconfiguration can be comprised of a superposition of a sine-like firstwave and a second wave having a corresponding shape to yield thealternating straight and curved sections when added to the sine-likefirst wave. One purpose of the first waveform is to minimize disruptionin large-scale features in the dimple pattern. One purpose of the secondwaveform is to allow the parting line to interdigitate between thedimples. The exact shape of the second waveform is determined by theparticular dimple layout at the parting line.

As described, the parting line 16 crosses back and forth across theequator E as it follows the circumference of the golf ball. The partingline 16 can also be described in terms of its angular deviation from theequator E. In preferred implementations, the parting line 16 is withinabout a 3° latitude band on either side of the equator, and morepreferably, within about a 1.5° band. Referring again to FIG. 2A, whichshows a magnified view of a segment of the parting line 16, thejunctions between the curved segments 20 and the straight segments 22preferably have fillets 30 or are otherwise rounded to provide a smoothtransition and avoid sharp edges.

FIG. 3 is a side elevation view, in section, of a representative mold 40for making a golf ball as described above. The mold 40 comprises anupper mold section 41 and a lower mold section 43 that are joinedtogether at the parting line 16 to define a cavity of a generallyspherical shape and having an inner surface 45. The inner surface of thecavity has projections 47 corresponding to the dimples 18 on the golfball that are positioned and sized according to the selected dimplepattern.

FIG. 4 is a perspective view of the lower mold section 43. The surfacesthat meet to define the parting line 16 include the curved segmentsurfaces 49 and the alternating straight segment surfaces 51. In theillustrated implementation, there are 30 curved segment surfaces and 30straight segment surfaces around the circumference of the mold. Althoughnot specifically shown, the upper mold section 41 has a correspondingnumber and arrangement of curved segment surfaces and straight segmentsurfaces. In the upper mold section, the parting line contour isreversed, i.e., the curved segments are concave at locations where thecorresponding bottom mold section has convex curved segments. This meansthat the top and bottom mold halves are not identical with regard to theparting line section.

Because the parting line is shaped to curve around most of the borderingdimples rather than to intersect with them, the parting line allows thedimples to be placed closer together than in a golf ball of aconventional design with a flat seam.

In view of the many possible embodiments to which the principles of thepresent disclosure can be applied, it should be recognized that theillustrated embodiments are only examples and should not be taken aslimiting the scope of the following claims. We therefore claim all thatcomes within the scope and spirit of these claims.

What is claimed is:
 1. A golf ball, comprising: two generallyhemispherical portions joined together at a parting line and comprisingdimples on respective outer surfaces thereof; the parting linecomprising a repeating pattern of curved segments alternating withstraight segments, wherein the parting line crosses the geometricequator of the golf ball; wherein the parting line intersects at leastone dimple bordering the equator.
 2. The golf ball of claim 1, whereinthe straight segments of the parting line are spaced apart from theequator.
 3. The golf ball of claim 1, wherein the curved segments of theparting line have their respective inflection points on a first side ofthe equator and the straight segments of the parting line are on asecond side of the equator opposite the first side.
 4. The golf ball ofclaim 1, wherein the repeating pattern is repeated approximately every72 degrees about each hemispherical portion.
 5. The golf ball of claim1, wherein the curved segments and the straight segments are joinedtogether at junctions each having a fillet radius.
 6. The golf ball ofclaim 1, wherein the parting line intersects exactly one dimple.
 7. Thegolf ball of claim 1, wherein the parting line extends between dimplesexcept at the point where the parting line intersects the at least onedimple.
 8. The golf ball of claim 1, wherein each of the curved segmentscrosses the geometric equator of the golf ball.
 9. The golf ball ofclaim 1, wherein none of the straight segments crosses the geometricequator of the golf ball.
 10. A golf ball, comprising: two generallyhemispherical portions joined together at a parting line and comprisingdimples on respective outer surfaces thereof; the parting line beingdefined by a first function comprising a sine-like wave superposed witha second function to yield a repeating pattern of curved segmentsalternating with straight segments; wherein the parting line extendsabout the golf ball, intersecting a bordering dimple and remainingspaced apart from other bordering dimples.
 11. The golf ball of claim10, wherein the parting line has a maximum peak-to-peak amplitude of 3°.12. The golf ball of claim 10, wherein the parting line has a maximumpeak-to-peak amplitude of 1.5°.
 13. The golf ball of claim 10, whereinthe two generally hemispherical portions are slightly asymmetricalrelative to each other.
 14. The golf ball of claim 10, wherein the golfball has a geometric equator, and wherein the geometric equator extendsaround the golf ball and the parting line oscillates about the equatoras the parting line extends around the golf ball.
 15. The golf ball ofclaim 14, wherein the curved segments of the parting line have theirrespective inflection points on a first side of the equator and thestraight segments of the parting line are on a second side of theequator opposite the first side.
 16. The golf ball of claim 10, whereinthe repeating pattern is repeated approximately every 72 degrees abouteach hemispherical portion.
 17. The golf ball of claim 10, wherein thecurved segments and the straight segments are joined together atjunctions each having a fillet radius.
 18. The golf ball of claim 10,wherein the parting line is bordered by about 30 dimples on each side.19. The golf ball of claim 10, wherein the parting line is bounded by1.5 degree latitude lines on either side of the equator.
 20. A golf ballmold, comprising: upper and lower sections each having projections forforming dimples in an outer surface of a golf ball; mating surfaces onthe upper and lower sections comprising curved segment forming surfacesalternating with straight segment forming surfaces; wherein one of themating surfaces intersects with one of the projections so that aresulting segment of the parting line on the golf ball will intersect adimple on the golf ball; wherein all other mating surfaces are spacedfrom the projections such that the remaining curved segments andremaining straight segments of the parting line to be formed on the golfball do not intersect any of the dimples.